Lightroom 6 hangs every time I change to Develop tab

I've just bought Lightroom 6 few days ago and still cannot use it! Lightroom crashes every time I change the tab from Library to Develop. I made an update to 6.1 and problem is still present. How to solve it? I'm quite frustrated due to the new software which isn't working.

It hangs. I use Windows 8/8.1 (upgraded, it is a little different than "new" 8.1) and ATI HD series 7. Driver is up to date (v. 15.20) and thus is outside this notice (https://helpx.adobe.com/lightroom/kb/...).